Did the NYPD nearly derail the investigation into one of the most serious post-9/11 terrorism plots — a conspiracy to bomb the New York City subway system?

Last year, two Associated Press reporters won a Pulitzer for saying exactly that, amid a series of articles “exposing” the activities of the Police Department’s intelligence unit, which they present as useless at best and guilty of profiling at worst — despite unearthing no evidence of any illegality.

Now the two are back with a book that recycles and re-hypes their old series. The danger is that ordinary New Yorkers who don’t follow this story will be misled by claims that are sensational only when ripped far out of context.

We’ll just deal with the one we mentioned up top. This is the charge that the cops botched the hunt for Najibullah Zazi, an al Qaeda-trained terrorist in Colorado who was heading to New York with explosives to blow up the subways. On his way across the George Washington Bridge, Zazi was stopped by Port Authority police acting on FBI direction. Unfortunately, they didn’t search his trunk. We don’t know why the trunk wasn’t searched, or what direction the Port Authority had from the FBI, but it’s surely not the NYPD’s fault that Zazi got through.

The FBI let the NYPD know Zazi was in New York. So police went to an imam who was an informant, showed him Zazi’s photo and asked if he’d seen him. When the cops left, the imam called Zazi to let him know authorities were looking for him — which is the main basis for the authors’ assertion (which appears encouraged by the FBI) that the NYPD’s intelligence unit is useless or counterproductive or both.

In any event, it turned out Zazi had already grown suspicious that he was under surveillance and had dumped his explosives. He flew back to Colorado, where he was arrested. A grand jury charged him with conspiring to use weapons of mass destruction. And New York didn’t suffer a terrorist attack, which it hasn’t during Ray Kelly’s reign as commissioner.

So here’s the question for our AP friends: If you’re the police and you learn a terrorist is in town and planning to blow up your subways, wouldn’t you do all you can to find him? The authors don’t seem to realize the Zazi case is an example of what cops should be doing, not what they shouldn’t.